1. Field of the Invention
This invention relates to a support system for a catheter, specifically for a guiding catheter used in coronary treatment.
It was particularly devised for use in the technique of percutaneous transluminum coronary angioplasty (PCTA) which involves the passage of a balloon catheter inside a larger and firmer guiding catheter to the coronary artery.
One role of the guiding catheter is to provide a channel for monitoring of blood pressure and for the injection of X-ray contrast material. Another role is to provide support for manipulation of the balloon catheter, especially during the actual crossing of tight stenoses or blockages.
2. Description of the Prior Art
Currently available guiding catheters are larger and firmer versions of angiographic catheters which are primarily designed to give contrast injections for X-ray purposes, rather than to provide anchorage at the site of entry to the coronary artery. Many instances of failure of PTCA procedures are due to this lack of support by the guiding catheter.
The problem of insecure anchorage may also affect other angioplasty devices which have been proposed, for example cutters, lasers and drills.
It has been proposed in U.S. Pat. No. 4,813,930 to Elliott to provide an angioplasty guiding catheter having a primary lumen to act as a guide for a balloon catheter or similar device and a secondary lumen in which one or more bracing wires are provided. The secondary lumen is apertured at a position spaced from the distal end of the catheter and endwise pressure can be exerted on the wire or wires which may project in one or more loops so as to be braced against the wall of a vessel and to hold the catheter in place.
However, the use of either one or two wires is objectionable in that the pressure exerted on the vessel wall may cause damage at the point or points of bracing contact because the wire or wires tend to embed in the wall of the vessel. Similarly, damage may be caused when withdrawing the catheter. Where only a single bracing wire is provided, there is a danger that the catheter may be insufficiently braced against lateral movement and may suddenly give way if a lateral force is exerted upon it by the insertion or manipulation of for example a balloon catheter.
Furthermore, the position at which the catheter is braced is spaced from the catheter at the distal end so that the tip itself of the catheter is not supported.